1. Field of the Invention
The present invention relates to a method for controlling a preview apparatus (for confirming the depth of field) in a single lens reflex camera having an AF (automatic focusing) function.
2. Description of the Related Art
In general, in a known single lens reflex camera having a preview apparatus, a release switch (release button) and a preview switch are separately provided. In an AF (automatic focusing) single lens reflex camera, the AF operation is carried out when the release switch is depressed by half step (i.e., when the photometering switch is turned ON). Since the preview switch is not related to the AF operation, if the preview switch is depressed in an out-of-focus state, the depth of field of an object image in the out-of-focus state is confirmed. Consequently, in order to confirm the depth of field of an object image in an in-focus state, it is necessary to first depress the release button by half step to perform the AF operation and thereafter to depress the preview switch after the composition is determined. Thus, in the conventional single lens reflex camera having an AF function, the photographer must actuate two different switches upon previewing. In particular, the photographer must carry out troublesome operations to confirm the depth of field at different object distances or in various compositions.
It is an object of the present invention to provide a control method of a preview apparatus in an AF single lens reflex camera in which the composition and the depth of field of an in-focus object can be easily and fast confirmed only by the operation of the preview switch without actuating the release switch.